What is metabolism?

What is metabolism?

The word “metabolism” is thrown around a lot these days, but what really IS metabolism?

You might have heard that if your metabolism is too slow, you might gain weight.  But what exactly does this all mean?

“Metabolism” describes all of the biochemical reactions in your body.  It’s how you take in nutrients and oxygen and use them to fuel everything you do.

Your body has an incredible ability to grow, heal, and stay alive, but without this amazing biochemistry, you would not be possible as a living, functioning human being.

Metabolism includes how the cells in your body:

• Allow activities you CAN control, such as physical activity;
• Allow activities you CAN’T control, such as your heart beating, wounds healing, and nutrient and toxin processing; and
• Allow storage of excess energy for use by the body later on.

So, you can imagine that some of these metabolism-related processes can sometimes move too quickly, too slowly, or just right, hence the variations in metabolism among different individuals.

Metabolic rate

This brings us to metabolic rate, which refers to how quickly your metabolism works and is measured in calories (yes, those famous calories we can’t seem to escape!).  The calories you eat can be funneled into one of three areas:

• Work, such as exercise and other activities;
• Heat, from all of those biochemical reactions; and
• Storage, as evidenced in leftover, “unburned” calories that are stored as fat.

The more calories you burn through work or by creating heat, the easier it is to lose weight and keep it off because there will be fewer leftover calories to store as fat.

There are a couple of different ways to measure metabolic rate: 

• Resting Metabolic Rate (RMR), which demonstrates how much energy your body uses when you’re not being physically active; and
• Total Daily Energy Expenditure (TDEE), which measures both the Resting Metabolic Rate as well as the energy used for work–such as exercise–throughout a 24-hour period.

What affects your metabolic rate?

In a nutshell: a lot!  The first thing you may think of is your thyroid.  This gland at the front of your throat releases hormones to tell your body to speed up your metabolism.  Of course, the more thyroid hormone that is available, the faster your metabolism will work and the more calories you’ll burn.

But your thyroid isn’t the only factor that affects your metabolic rate.  Your size counts, too!  Larger people have higher metabolic rates, but their body composition is equally important.

Muscles that are actively moving and working efficiently need more energy than fat does, so the greater your lean muscle mass,  the more energy your body will burn and the higher your metabolic rate will be, even when you’re not working out.  This is exactly why weight/strength training is highly recommended as a part of a weight loss program.  You want your muscles to be burning those calories for you! 

Here’s the thing:  when people lose weight, their metabolic rate often slows down–a move that you don’t want to happen.  So you definitely want to offset weight loss with increased muscle mass.

Aerobic exercise also temporarily increases your metabolic rate.  Here, your muscles are burning fuel as you move energetically, so they’re doing “work.”

The type of food you eat is another factor that affects your metabolic rate.  Your body burns calories to absorb, digest, and metabolize your food, a process known as the Thermic Effect of Food (TEF).  You can use it to your advantage when you understand how your body metabolizes foods differently. 

Fats, for example, increase your TEF by 0-3%, carbs increase it by 5-10%, and protein increases it by 15-30%.  By trading some of your fat or carbs for lean protein, you can slightly increase your metabolic rate.

Protein is necessary for muscle growth, so by working your muscles and feeding them from food groups on which they thrive, you will continue to lose weight and keep it off.

But please don’t forget the mind-body connection.  There is plenty of research that demonstrates the effect of mood, stress, and sleep on your metabolic rate.

We’ve just scratched the surface in this post regarding metabolism and how so many different factors can influence whether your metabolic rate increases, decreases, or remains relatively static.  But check out this recipe that provides a healthy dose of lean protein to help keep your metabolism elevated!

Lemon Herb Roasted Chicken Breasts (serves 4)

Ingredients

• 2 lemons, sliced
• 1 tablespoon rosemary
• 1 tablespoon thyme
• 2 cloves garlic, thinly sliced
• 4 boneless, skinless chicken breasts 
• dash salt and pepper
• 1 tablespoon extra virgin olive oil

Directions

1. Preheat oven to 425 F. 
2. Layer half of the lemon slices on the bottom of a baking dish.  Sprinkle with half of the herbs and half of the sliced garlic.
3. Place the chicken breasts on top of the lemon slices, herbs, and garlic and sprinkle with salt and pepper.  Place remaining lemon, herbs, and garlic on top of the chicken.  Drizzle with olive oil.  Cover with a lid or foil.
4. Bake for 45 minutes until chicken is cooked through.  If you want the chicken to be a bit more “roasty,” remove the lid/foil and broil for another few minutes (watch it carefully so that it doesn’t burn!).
5. Serve and enjoy!

Tip: You can add leftover sliced chicken breast to your salad for lunch the next day!

P.S.  Love this recipe?  Join me in my Facebook group for even more awesome recipes every Wednesday. Check it out here: —> https://bit.ly/2NsBrt8

References:

http://www.precisionnutrition.com/all-about-energy-balance

https://authoritynutrition.com/10-ways-to-boost-metabolism/

What have you observed about your metabolism?  How would you describe it: slow, fast, or normal?